Heretofore, it has been known that a base sequence for protein expression in which a cis element consisting of a particular base sequence is linked to a promoter of a particular gene that yields protein, when producing protein such as a diastatic enzyme using koji mold (see e.g., Patent Literatures 1 and 2). The conventional base sequence for protein expression can improve the activity of the promoter and can increase the yield of the protein, by linking the cis element to the promoter.
For example, Patent Literature 1 describes a technique of using enhancer DNA consisting of a XlnR/Ace2 binding sequence and a Hap complex binding sequence as a cis element and linking 12 cis elements upstream (on the 5′-terminal side) of a promoter of tef1 gene. According to Patent Literature 1, in this way, GUS activity by the promoter is reported to be improved approximately 4.9 times under solid culture conditions with wheat bran as a carbon source.
Also, Patent Literature 2 describes a technique of using enhancer DNA located at a promoter of α-glucosidase gene of koji mold (Aspergillus oryzae) as a cis element and linking 12 such cis elements upstream (on the 5′-terminal side) of the promoter. According to Patent Literature 2, in this way, GUS activity by the promoter is reported to be improved approximately 6 times under culture conditions with starch as a carbon source.